3G Tutorial

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Slide 1 : 3G Tutorial Brough Turner & Marc Orange Originally presented at Fall VON 2002
Slide 2 : Preface... The authors would like to acknowledgement material contributions from: Murtaza Amiji, NMS Communications Samuel S. May, Senior Research Analyst, US Bancorp Piper Jaffray Others as noted on specific slides We intend ongoing improvements to this tutorial and solicit your comments at: rbt@nmss.com and/or marc_orange@nmss.com For the latest version go to: http://www.nmscommunications.com/3Gtutorial
Slide 3 : Outline History and evolution of mobile radio Brief history of cellular wireless telephony Radio technology today: TDMA, CDMA Demographics and market trends today 3G vision, 3G migration paths Evolving network architectures Based on GSM-MAP or on IS-41 today 3GPP versus 3GPP2 evolution paths 3G utilization of softswitches, VoIP and SIP Potential for convergence
Slide 4 : Slide 4 Outline (continued) Evolving services SMS, EMS, MMS messaging Location Video and IP multimedia Applications & application frameworks Is there a Killer App? Business models What’s really happening? When?
Slide 5 : 3G Tutorial History and Evolution of Mobile Radio Evolving Network Architectures Evolving Services Applications Business Models
Slide 6 : First Mobile Radio Telephone 1924 Courtesy of Rich Howard
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Slide 8 : Cellular Mobile Telephony Frequency modulation Antenna diversity Cellular concept Bell Labs (1957 & 1960) Frequency reuse Typically every 7 cells Handoff as caller moves Modified CO switch HLR, paging, handoffs Sectors improve reuse Every 3 cells possible
Slide 9 : First Generation Advanced Mobile Phone Service (AMPS) US trials 1978; deployed in Japan (’79) & US (’83) 800 MHz band — two 20 MHz bands TIA-553 Still widely used in US and many parts of the world Nordic Mobile Telephony (NMT) Sweden, Norway, Demark & Finland Launched 1981; now largely retired 450 MHz; later at 900 MHz (NMT900) Total Access Communications System (TACS) British design; similar to AMPS; deployed 1985 Some TACS-900 systems still in use in Europe
Slide 10 : Second Generation — 2G Digital systems Leverage technology to increase capacity Speech compression; digital signal processing Utilize/extend “Intelligent Network” concepts Improve fraud prevention Add new services There are a wide diversity of 2G systems IS-54/ IS-136 North American TDMA; PDC (Japan) iDEN DECT and PHS IS-95 CDMA (cdmaOne) GSM
Slide 11 : D-AMPS/ TDMA & PDC Speech coded as digital bit stream Compression plus error protection bits Aggressive compression limits voice quality Time division multiple access (TDMA) 3 calls per radio channel using repeating time slices Deployed 1993 (PDC 1994) Development through 1980s; bakeoff 1987 IS-54 / IS-136 standards in US TIA ATT Wireless & Cingular use IS-136 today Plan to migrate to GSM and then to W-CDMA PDC dominant cellular system in Japan today NTT DoCoMo has largest PDC network
Slide 12 : iDEN Used by Nextel Motorola proprietary system Time division multiple access technology Based on GSM architecture 800 MHz private mobile radio (PMR) spectrum Just below 800 MHz cellular band Special protocol supports fast “Push-to-Talk” Digital replacement for old PMR services Nextel has highest APRU in US market due to “Direct Connect” push-to-talk service
Slide 13 : DECT and PHS Also based on time division multiple access Digital European Cordless Telephony Focus on business use, i.e. wireless PBX Very small cells; In building propagation issues Wide bandwidth (32 kbps channels) High-quality voice and/or ISDN data Personal Handiphone Service Similar performance (32 kbps channels) Deployed across Japanese cities (high pop. density) 4 channel base station uses one ISDN BRI line Base stations on top of phone booths Legacy in Japan; new deployments in China today
Slide 14 : North American CDMA (cdmaOne) Code Division Multiple Access All users share same frequency band Discussed in detail later as CDMA is basis for 3G Qualcomm demo in 1989 Claimed improved capacity & simplified planning First deployment in Hong Kong late 1994 Major success in Korea (1M subs by 1996) Used by Verizon and Sprint in US Simplest 3G migration story today
Slide 15 : cdmaOne — IS-95 TIA standard IS-95 (ANSI-95) in 1993 IS-95 deployed in the 800 MHz cellular band J-STD-08 variant deployed in 1900 MHz US “PCS” band Evolution fixes bugs and adds data IS-95A provides data rates up to 14.4 kbps IS-95B provides rates up to 64 kbps (2.5G) Both A and B are compatible with J-STD-08 All variants designed for TIA IS-41 core networks (ANSI 41)
Slide 16 : GSM « Groupe Special Mobile », later changed to « Global System for Mobile » Joint European effort beginning in 1982 Focus on seamless roaming across Europe Services launched 1991 Time division multiple access (8 users per 200KHz) 900 MHz band; later extended to 1800MHz Added 1900 MHz (US PCS bands) GSM is dominant world standard today Well defined interfaces; many competitors Network effect (Metcalfe’s law) took hold in late 1990s Tri-band GSM phone can roam the world today
Slide 17 : Distribution of GSM Subscribers GSM is used by 70% of subscribers worldwide 564 M subs / 800 M subs in July 2001 Most GSM deployments in Europe (59%) and Asia (33%) ATT & Cingular deploying GSM in US today Source: EMC World Cellular / GSM Association
Slide 18 : 1G — Separate Frequencies
Slide 19 : 2G — TDMA Time Division Multiple Access
Slide 20 : 2G & 3G — CDMA Code Division Multiple Access Spread spectrum modulation Originally developed for the military Resists jamming and many kinds of interference Coded modulation hidden from those w/o the code All users share same (large) block of spectrum One for one frequency reuse Soft handoffs possible Almost all accepted 3G radio standards are based on CDMA CDMA2000, W-CDMA and TD-SCDMA
Slide 21 : Multi-Access Radio Techniques Courtesy of Petri Possi, UMTS World
Slide 22 : Courtesy of Suresh Goyal & Rich Howard
Slide 23 : Courtesy of Suresh Goyal & Rich Howard
Slide 24 : Courtesy of Suresh Goyal & Rich Howard
Slide 25 : Courtesy of Suresh Goyal & Rich Howard
Slide 26 : 3G Vision Universal global roaming Multimedia (voice, data & video) Increased data rates 384 kbps while moving 2 Mbps when stationary at specific locations Increased capacity (more spectrally efficient) IP architecture Problems No killer application for wireless data as yet Vendor-driven
Slide 27 : International Standardization ITU (International Telecommunication Union) Radio standards and spectrum IMT-2000 ITU’s umbrella name for 3G which stands for International Mobile Telecommunications 2000 National and regional standards bodies are collaborating in 3G partnership projects ARIB, TIA, TTA, TTC, CWTS. T1, ETSI - refer to reference slides at the end for names and links 3G Partnership Projects (3GPP & 3GPP2) Focused on evolution of access and core networks
Slide 28 : IMT-2000 Vision Includes LAN, WAN and Satellite Services
Slide 29 : IMT-2000 Radio Standards IMT-SC* Single Carrier (UWC-136): EDGE GSM evolution (TDMA); 200 KHz channels; sometimes called “2.75G” IMT-MC* Multi Carrier CDMA: CDMA2000 Evolution of IS-95 CDMA, i.e. cdmaOne IMT-DS* Direct Spread CDMA: W-CDMA New from 3GPP; UTRAN FDD IMT-TC** Time Code CDMA New from 3GPP; UTRAN TDD New from China; TD-SCDMA IMT-FT** FDMA/TDMA (DECT legacy) * Paired spectrum; ** Unpaired spectrum
Slide 30 : CDMA2000 Pros and Cons Evolution from original Qualcomm CDMA Now known as cdmaOne or IS-95 Better migration story from 2G to 3G cdmaOne operators don’t need additional spectrum 1xEVD0 promises higher data rates than UMTS, i.e. W-CDMA Better spectral efficiency than W-CDMA(?) Arguable (and argued!) CDMA2000 core network less mature cmdaOne interfaces were vendor-specific Hopefully CDMA2000 vendors will comply w/ 3GPP2
Slide 31 : W-CDMA (UMTS) Pros and Cons Wideband CDMA Standard for Universal Mobile Telephone Service (UMTS) Committed standard for Europe and likely migration path for other GSM operators Leverages GSM’s dominant position Requires substantial new spectrum 5 MHz each way (symmetric) Legally mandated in Europe and elsewhere Sales of new spectrum completed in Europe At prices that now seem exorbitant
Slide 32 : TD-SCDMA Time division duplex (TDD) Chinese development Will be deployed in China Good match for asymmetrical traffic! Single spectral band (1.6 MHz) possible Costs relatively low Handset smaller and may cost less Power consumption lower TDD has the highest spectrum efficiency Power amplifiers must be very linear Relatively hard to meet specifications
Slide 33 : Migration To 3G
Slide 34 : Source: U.S. Bancorp Piper Jaffray Subscribers: GSM vs CDMA Cost of moving from GSM to cdmaOne overrides the benefit of the CDMA migration path
Slide 35 : Mobile Wireless Spectrum
Slide 36 : Prospects for Global Roaming Multiple vocoders (AMR, EVRC, SMV,…) Six or more spectral bands 800, 900, 1800, 1900, 2100, 2500, …? MHz At least four modulation variants GSM (TDMA), W-CDMA, CDMA2000, TD-SCMDA The handset approach Advanced silicon Software defined radio Improved batteries Two cycles of Moore’s law? i.e. 3 yrs?
Slide 37 : 3G Tutorial History and Evolution of Mobile Radio Evolving Network Architectures Evolving Services Applications Business Models
Slide 38 : Evolving CN Architectures Two widely deployed architectures today GSM-MAP — used by GSM operators “Mobile Application Part” defines extra (SS7-based) signaling for mobility, authentication, etc. ANSI-41 MAP — used with AMPS, TDMA & cdmaOne TIA (ANSI) standard for “cellular radio telecommunications inter-system operation” Each evolving to common “all IP” vision “All IP” still being defined — many years away GAIT (GSM ANSI Interoperability Team) provides a path for interoperation today
Slide 39 : BTS — Base Transceiver Station BSC — Base Station Controller Typical 2G Architecture MSC — Mobile Switching Center VLR — Visitor Location Register HLR — Home Location Register
Slide 40 : MSC HLR Network Planes Like PSTN, 2G mobile networks have one plane for voice circuits and another plane for signaling Some elements reside only in the signaling plane HLR, VLR, SMS Center, … MSC VLR Transport Plane (Voice) Signaling Plane (SS7) MSC SMS-SC
Slide 41 : Signaling in Core Network Based on SS7 ISUP and specific Application Parts GSM MAP and ANSI-41 services Mobility, call-handling, O&M Authentication, supplementary services SMS, … Location registers for mobility management HLR: home location register has permanent data VLR: visitor location register keeps local copy for roamers
Slide 42 : PSTN-to-Mobile Call (STP) (SCP) PSTN PLMN (SSP) (SSP) BSS MS PLMN (Home) (Visitor) (STP) HLR GMSC (SSP) VMSC VLR SCP
Slide 43 : BSS — Base Station System BTS — Base Transceiver Station BSC — Base Station Controller MS — Mobile Station NSS — Network Sub-System MSC — Mobile-service Switching Controller VLR — Visitor Location Register HLR — Home Location Register AuC — Authentication Server GMSC — Gateway MSC GSM 2G Architecture GSM — Global System for Mobile communication
Slide 44 : Enhancing GSM New technology since mid-90s Global standard — most widely deployed significant payback for enhancements Frequency hopping Overcome fading Synchronization between cells DFCA: dynamic frequency and channel assignment Allocate radio resources to minimize interference Also used to determine mobile’s location TFO — Tandem Free Operation
Slide 45 : TFO Concepts Improve voice quality by disabling unneeded transcoders during mobile-to-mobile calls Operate with existing networks (BSCs, MSCs) New TRAU negotiates TFO in-band after call setup TFO frames use LSBits of 64 Kbps circuit to carry compressed speech frames and TFO signaling MSBits still carry normal G.711 speech samples Limitations Same speech codec in each handset Digital transparency in core network (EC off!) TFO disabled upon cell handover, call transfer, in-band DTMF, announcements or conferencing
Slide 46 : TFO – Tandem Free Operation No TFO : 2 unneeded transcoders in path With TFO (established) : no in-path transcoder A BTS BSC Ater MSC MSC BSC MS MS BTS Abis GSM Coding G.711 / 64 kb GSM Coding CD DC CD DC (**) or 7 bits if Half-Rate coder is used A BTS BSC Ater MSC MSC BSC MS MS BTS Abis GSM Coding [GSM Coding + TFO Sig] (2bits) + G.711 (6bits**) / 64 Kb GSM Coding CD TFO TFO DC PSTN* PSTN* (*) or TDM-based core network
Slide 47 : New Vocoders: AMR & SMV AMR: Adaptive multi-rate Defined for UMTS (W-CDMA) Being retrofitted for GSM SMV: Selectable mode vocoder Defined by 3GPP2 for CDMA2000 Many available coding rates AMR 8 rates: 12.2, 10.2, 7.95, 7.4, 6.7, 5.9, 5.15 & 4.75bps, plus silence frames (near 0 bps) SMV 4 rates: 8.5, 4, 2 & 0.8kbps Lower bit rates allow more error correction Dynamically adjust to radio interference conditions
Slide 48 : Enhancing GSM AMR speech coder Trade off speech and error correction bits Fewer dropped calls DTX — discontinuous transmission Less interference (approach 0 bps during silences) More calls per cell Overlays, with partitioned spectral reuse 3x in overlay (cell edges); 1x reuse in underlay HSCSD — high speed circuit-switched data Aggregate channels to surpass 9.6 kbps limit (?50k) GPRS — general packet radio service
Slide 49 : GPRS — 2.5G for GSM General packet radio service First introduction of packet technology Aggregate radio channels Support higher data rates (115 kbps) Subject to channel availability Share aggregate channels among multiple users All new IP-based data infrastructure No changes to voice network
Slide 50 : 2.5G / 3G Adds IP Data No Changes for Voice Calls
Slide 51 : BSS — Base Station System BTS — Base Transceiver Station BSC — Base Station Controller NSS — Network Sub-System MSC — Mobile-service Switching Controller VLR — Visitor Location Register HLR — Home Location Register AuC — Authentication Server GMSC — Gateway MSC 2.5G Architectural Detail SGSN — Serving GPRS Support Node GGSN — Gateway GPRS Support Node GPRS — General Packet Radio Service 2G MS (voice only)
Slide 52 : GSM Evolution for Data Access 1997 2000 2003 2003+ GSM GPRS EDGE UMTS 9.6 kbps 115 kbps 384 kbps 2 Mbps GSM evolution 3G
Slide 53 : EDGE Enhanced Data rates for Global Evolution Increased data rates with GSM compatibility Still 200 KHz bands; still TDMA 8-PSK modulation: 3 bits/symbol give 3X data rate Shorter range (more sensitive to noise/interference) GAIT — GSM/ANSI-136 interoperability team Allows IS-136 TDMA operators to migrate to EDGE New GSM/ EDGE radios but evolved ANSI-41 core network
Slide 54 : 3G Partnership Project (3GPP) 3GPP defining migration from GSM to UMTS (W-CDMA) Core network evolves from GSM-only to support GSM, GPRS and new W-CDMA facilities 3GPP Release 99 Adds 3G radios 3GPP Release 4 Adds softswitch/ voice gateways and packet core 3GPP Release 5 First IP Multimedia Services (IMS) w/ SIP & QoS 3GPP Release 6 “All IP” network; contents of r6 still being defined
Slide 55 : 3G rel99 Architecture (UMTS) — 3G Radios SS7 IP BTS BSC MSC VLR HLR AuC GMSC BSS SGSN GGSN PSTN PSDN CN Gs BSS — Base Station System BTS — Base Transceiver Station BSC — Base Station Controller RNS — Radio Network System RNC — Radio Network Controller CN — Core Network MSC — Mobile-service Switching Controller VLR — Visitor Location Register HLR — Home Location Register AuC — Authentication Server GMSC — Gateway MSC SGSN — Serving GPRS Support Node GGSN — Gateway GPRS Support Node A E PSTN 2G MS (voice only) 2G+ MS (voice & data) UMTS — Universal Mobile Telecommunication System Gb
Slide 56 : 3G rel4 Architecture (UMTS) — Soft Switching
Slide 57 : Transcoder Free Operation (TrFO) Improve voice quality by avoiding unneeded transcoders like TFO but using packet-based core network Out-of-band negociation Select same codec at both ends during call setup Supports sudden channel rearrangement (handovers, etc.) via signaling procedures When TrFO impossible, TFO can be attempted e.g. transit between packet-based and circuit-based core networks
Slide 58 : TrFO + TFO Example 2G handset to 3G handset: by combining TrFO and TFO, in-path transcoders can be avoided 3G Packet Core Network 3G UE Radio Access Network 2G PLMN MSC Server CS-MGW CS-MGW GMSC Server MSC GSM Coding (TrFO) GSM Coding CD DC TFO [GSM Coding + TFO Sig] (lsb) + G.711 (msb) / 64 Kb TFO Radio Access Network 2G MS
Slide 59 : 3G rel5 Architecture (UMTS) — IP Multimedia
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